We have established that the L-system of amino acid transport is invariably, and markedly impaired in the lymphocytes from patients with B-cell chronic lymphocytic leukemia (CLL). This highly specific difference between CLL B-cells and normal B-cells will be exploited in an effort to isolate and characterize the protein or proteins responsible for l-system transport. The membrane proteins from normal and CLL B-lymphocytes will be separated using two dimensional gel electrophoresis. Two methods will be used to identify the L-system transport protein or proteins on two dimensional gels. Monoclonal antibodies that react specifically with the L-system will be generated by making mice tolerant to CLL B-lymphocytes which are deficient in the L-system and subsequently immunizing the mice with normal B-lymphocytes which have an intact L-system. The monoclonal antibodies will be screened for reactivity to normal but not CLL B-cells. Monoclonal antibodies binding to normal B but not CLL B-cells will be screened for functional inhibition of the L-system. Such antibodies can be used to extend the sensitivity of two dimensional gel electrophoresis for localization of the L-system transport protein. In addition, photoreactive radiolabelled amino acids which can be bound specifically to the L-system site will be used to identify the transport protein on two dimensional gels. As an extension of previous investigations we will determine whether the L-system transport in the T-lymphocyte population in CLL-B-cell leukemia accounts for the 10% residual transport that is measured. We will separate the T-lymphocyte population from B-cell CLL blood using a sepharose anti-immunoglobulin affinity column, and the measurements of L-system transport will be correlated with the cytogenetics of the B and T-cell populations. Further, CLL B-cells will be treated with mitogenic (cytochalasin B, staph protein A) and maturational (phorbol esters) agents to determine the effect of 1) new DNA synthesis or 2) expression of the plasma cell phenotype on the ability to acquire a heightened capacity of L-system transport. These studies will assess whether the impaired L-system is related to a diminished proliferative capacity or arrested maturation.